/**
 * @file Name: 10.cpp
 * @author: Fenghuwuyu
 * @version: 1.0
 * @brief:
 * @date: Sat 22 May 2021 10:05:30 PM PDT
 */

#include<iostream>
int main()


//
//  the standard header <cstddef> contains a definition of the alias size_t:
//  using size_t = unsigned int;
//
//  In fact, every standard-library container provides value_type as the name of its value type, for example:
//
//  template<typename C>
//  using Element_type = typename C::value_type;
